Negative pressure wound closure devices and methods

ABSTRACT

Systems, devices, and methods of the present application can accelerate and reduce medical complications associated with healing of amputation wounds. The devices and methods utilize a compression structure and negative pressure to cause the amputation wound to preferentially close from the deepest portion of the wound to the shallowest portion.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application62/267,728 filed Dec. 15, 2015, the entire contents of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

A variety of wounds are now being treated using negative pressure woundtherapy. However, many of these wounds have characteristics that limitthe effectiveness of existing techniques. Wound dehiscence, in which thewound margins have substantial separation, pose significant problems inreapproximation of tissue and wound drainage. For example, there are alarge number of patients undergoing amputations in the United Statesevery year. These have different causes including traumatic injury,peripheral vascular disease, diabetes mellitus and chronic venousinsufficiency. Patients with diabetic conditions, for example, oftensuffer from restricted blood flow that can lead to tissue necrosis atthe body extremities. For patients with severe symptoms, atransmetatarsal amputation (TMA) may be recommended to remove afflictedtissue while still salvaging a portion of the foot. In many cases, atranstibial or below-knee amputation (BKA) must be performed. Animportant factor in the recovery of a patient from amputation is howquickly the wound can be closed. Because the gap between tissue marginscan be large, the wound is manually closed by suturing. There must beongoing attention to prevent complications such as infection, wounddehiscence, and/or ischemia. The use of an immediate post-operativeprosthesis (IPOP) is commonly employed to reduce the recovery period forBKA procedures, for example.

Other examples of wounds that can be difficult to achieve approximationof the wound margins can include ulcers in which the wound opening issurrounded by tissue overlying a cavity. The undermining of the tissuesurrounding the wound opening can often present problems in drainage andrapid wound closure. There are also open wounds that can occur in boththe extremities and the abdominal regions in which the wound marginsmust rotate over a substantial distance, often up to several centimetersor more, to achieve approximation of the margins. Thus a continuing needexists for improvements in wound closure devices and methods.

SUMMARY OF THE INVENTION

This disclosure relates to embodiments of negative pressure woundclosure devices, systems, and methods for wounds resulting fromamputation or other open wounds having non-aligned wound margins. Inpreferred embodiments, the system includes a negative pressure sourceand a collapsing structure that is placed on the wound to providedirected preferential closure. The collapsing structure can includeembodiments in which a compressive force is imparted to tissuesurrounding the wound or to tissue on the sides of a wound opening thatis operative to assist in the closure of a wound cavity. Thus, thecollapsing structure can include, be attached to, or operate inconjunction with, a compression structure that operates to apply a forceto the tissue adjoining an open wound to move a wound margin to a moreclosed position. In a preferred embodiment, a collapsing compressionstructure includes a number of cells separated by rigid or semi-rigidmembranes that are hinged together at joints. The structure changesconformation during a procedure to facilitate closure of the wound. Thestructure, in combination with the application of negative pressure,exerts a force to the wound to facilitate closure of the wound from thedeepest internal point. The structure can be rigid, or alternatively, bepre-stressed to exert a compression force on the wound to more quicklybring the wound margins together.

The device can be used without any sutures in cases where the skin onopposite sides of the wound is sufficiently aligned. Alternatively,sutures can be used to provide alignment in the case of a wound wherethe margins and/or the overlying skin are not well aligned or are notamenable to restructuring to make them so aligned.

Wound closure of open wounds in which the wound margins are notsubstantially parallel can include the amputation of limbs or otherregions of the body having substantially curved contoured regions. Woundclosure devices fitting over and/or within the wound can require anarcuate shape to be effective to close such wounds. Often differentdepths within the wound will close at different rates upon theapplication of negative pressure. It is critical to provide arcuatelyshaped devices that are effective to close the deeper portions of thewound margins in advance of the shallower portions to avoid the creationof separated wound margin regions that are not visible.

Wound closure devices in accordance with the invention can include oneor more device components that are inserted within the wound tofacilitate wound closure. A preferred embodiment can employ a doublesided anchoring matrix that is inserted in all or a portion of the woundthat will attach to both wound margins. The matrix can have aperturesextending through the matrix to facilitate wound margin contact throughthe apertures. One or both sides of the matrix can have tissue anchorsto grasp the margin surfaces. Adhesive material can also be used as atissue anchor material. The matrix can comprise a bio-absorbablematerial that does not need to be removed from the wound upon woundclosure. A further preferred embodiment uses an arcuately shaped closuredevice in which an outer portion has a larger dimension then an innerportion as the outer portion has a substantially greater length uponinsertion into the wound.

In another preferred embodiment for treating an open wound, a commonproblem involves the drainage and closure of ulcerative conditions. Acollapsing structure using negative pressure around therapy and acompression device that is operative to apply a force to the tissuesurrounding the wound can also be used to facilitate wound closure. Thisprocedure can also be used with or without sutures to close the wound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wound closure device applied to a wound inaccordance with various embodiments of the present invention.

FIG. 2 illustrates a wound closure device applied to a wound afterinitial application of negative pressure in accordance with variousembodiments of the present invention.

FIG. 3 illustrates a wound closure device applied to a wound afterapplication of negative pressure in accordance with various embodimentsof the present invention.

FIG. 4 illustrates a wound closure device applied to a wound afterapplication of negative pressure in accordance with various embodimentsof the present invention.

FIG. 5A illustrates exemplary compression structures and cell shapes inaccordance with various aspects and embodiments of the presentinvention.

FIG. 5B illustrates a single cell shape of the structure shown in FIG.5A under compression.

FIGS. 5C and 5D illustrate three-dimensional representations ofexemplary compression structures in accordance with various embodimentsof the present invention.

FIGS. 5E and 5F illustrate top views of collapse of a wall of a cell ina compression structure according to various embodiments of the presentinvention.

FIG. 5G illustrates a perspective view of collapse of a wall of a cellin a compression structure according to various embodiments of thepresent invention.

FIG. 6 illustrates a wound closure device including additionalstructural and drainage elements according to some embodiments of theinvention.

FIGS. 7A and 7B illustrate an exemplary cell structure for a compressionstructure in accordance with various embodiments of the invention.

FIGS. 8A, 8B, and 8C illustrate further cell structure for a compressionstructure in accordance with various embodiments of the invention.

FIG. 9 illustrates an example anchoring system included in a woundclosure device in accordance with various embodiments of the presentinvention.

FIG. 10 illustrates several grasping features for an anchoring system inaccordance with embodiments of the present invention.

FIG. 11 is a schematic diagram of a surgical wound drainage device andrelated equipment according to some embodiments of the invention.

FIGS. 12A-C show illustrations of embodiments of an adhesion matrixhaving different types of tissue contact apertures. FIG. 12D is anillustration of an adhesion matrix embodiment possessing tissue anchorson its surface. FIG. 12E shows a cross-sectional view of the adhesionmatrix of FIG. 12D.

FIGS. 13A-13C illustrate end views of progressive steps of an exemplarycompression structure during compression in accordance with variousembodiments of the present invention.

FIGS. 13D-13F illustrate cross-sectional top views corresponding to theend views of FIGS. 13A-13C, respectively.

FIG. 13G illustrates a portion of a compression structure in an extendedstate in accordance with various embodiments of the present invention.

FIGS. 13H and 13I illustrate portions of the compression structure inextended and collapsed states, respectively, in accordance with variousembodiments of the present invention.

FIG. 13J illustrates a portion of a compression structure in a collapsedstate in accordance with various embodiments of the present invention.

FIG. 14 illustrates a wound closure device with enhanced forceapplication in accordance with various embodiments of the presentinvention.

FIG. 15A illustrates a cross-sectional view of a decubitis ulcer injuryin a tissue.

FIG. 15B illustrates a wound closure device applied to the decubitusulcer injury according to various embodiments of the present invention.

FIG. 15C illustrates the wound closure device of FIG. 15B uponapplication of negative pressure to the device in accordance withvarious embodiments of the present invention.

FIG. 15D illustrates the wound closure device of FIG. 15C wherein woundmargins are nearly approximated in accordance with various embodimentsof the present invention.

FIG. 15E illustrates a wound closure device that includes a surgicaldrain device in accordance with various embodiments of the presentinvention.

FIGS. 16A-16E illustrate wound closure devices to treat injuriescharacterized by undermining in accordance with various embodiments ofthe present invention.

FIG. 17 illustrates a methodology for wound healing and closure inaccordance with various embodiments of the present invention.

FIG. 18 illustrates a methodology for wound healing and closure inaccordance with various embodiments of the present invention.

FIG. 19 illustrates a methodology for wound healing and closure inaccordance with various embodiments of the present invention.

FIG. 20 illustrates a methodology for wound healing and closure inaccordance with various embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to negative pressure woundclosure devices, systems, and methods for wounds resulting fromamputation or other open wound in which the wound margins undergorotation to align and close. The embodiments as described herein includea negative pressure source and a compression structure that is placed onthe wound to provide directed preferential closure. The compressionstructure can include a number of cells separated by rigid or semi-rigidmembranes that are hinged together at joints. The structure changesconformation during a procedure to facilitate closure of the wound.

FIGS. 1-4 illustrate cross-sections of a wound closure device 100applied at a body extremity to a wound 150 caused by amputation. Thewound closure device 100 can include a compression structure 102, aninlet 105, and flaps 108. The wound closure device 100 can have adome-shaped geometry in order to extend around the limb in such a waythat the peripheral edge 101 of the dome fully surrounds the wound. Whena negative pressure is applied to the inlet 105, the compressionstructure 102 and flaps 108 can apply a force to the wound 150 that isstrongest at the deepest point of the wound 150 a. The compressionstructure 102 in combination with the application of negative pressurecan exert a force to the wound 150 to facilitate closure of the wound150 from the deepest internal point 150 a as illustrated in FIGS. 1-4and as described in further detail below. Application of the device canimpart a force to spaced-apart wound margins that is operable to movethe wound margins to a more closed position.

Although the wound closure device 100 is described as having a domeshape (i.e., a curvature along two axes), it is also contemplated thatembodiments of the present invention can have curvature in only onedimension (i.e., a cylindrical geometry). As a non-limiting example, awound closure device 100 in accordance with the present disclosure cancover a wound on a lateral surface of a bodily limb or extremity such asthe thigh. The device can have a range of values of curvature toaccommodate wounded extremities as varied as fingers or toes to legs orarms. In some embodiments, the radius of curvature of the device isdifferent from the radius of curvature of the tissue under treatmentsuch that, as a result, the device is at least partially spatiallyseparated from the tissue surface.

The wound 150 can have a width (X) 152 and a depth (Y) 154. In someembodiments, the depth 154 of the wound 150 can be between 0.1 and 1times the width 152 of the wound 150. Previously available treatmentsmay incompletely treat wounds with such large aspect ratios of depth towidth because they typically force the margins of the wound at a shallowportion 150 b of the wound to approximate (i.e., come into contact)before the margins of the wound at a deep portion 150 a of the wound. Inthe case where the shallow margins approximate first, the potentialarises for seroma formation or infection of the wound below the surface.Embodiments of the present invention can ameliorate this problem bypreferentially applying a greater lateral force 110 a at the deepportion 150 a of the wound 150 than at the shallow portion 150 b of thewound as will be described in more detail below.

The compression structure 102 can be situated outside of the wound asshown in FIG. 1A and can have a number of cells 103 separated by rigidor semi-rigid membranes 107 that are hinged together at joints. Theshape of the cells 103 can be selected based on the shape of the wound150. Details on the cell shape and composition will be described ingreater detail below with reference to FIG. 5. The compression structure102 can be pre-stressed to exert a compression force on the wound 150 tomore quickly bring the wound margins together. Certain elements or cellsof the compression structure can have greater compliance to enableinterdigitated collapse. In some embodiments, the compression structure102 can include a circle or spiral format that lays flat in or above thewound to achieve a similar collapsing effect. In various embodiments,the compression structure 102 can be symmetrical or asymmetrical. As thecompression structure collapses, the outermost surface of thecompression structure 102 can have a larger radius than the innermostsurface of the compression structure 102. Note that the walls ofadjoining cells extend at different angle due to the arced shape of thedevice that is needed to extend over the wound. For amputation wounds,the device must have a dome-shaped structure to enclose the woundopening at one end of the limb. In some embodiments, the compressionstructure 102 is a collapsible structure. The collapsible structure canhave a curved contour that extends over at least a portion of tissueadjacent to the wound or wound opening.

The flaps 108 can be attached to the compression structure 102 and canextend to the peripheral edge 101 of the wound closure device 100. Insome embodiments, the flaps 108 may include a first section 108 a and asecond section 108 b that are made of different materials or havedifferent properties. In certain embodiments, the first section 108 amay be more flexible, stretchable, or elastic than the second section108 b. In some embodiments, the first section 108 a, the second section108 b, or both may include anchoring elements 104. The anchoringelements 104 can be used with the flaps 108 on some or all sides of thewound 150 to attach the structure to a wrap 106 that surrounds the limbjust proximal to the wound opening. In some embodiments, the secondsection 108 b of the flaps 108 can be made of a stiff material that willnot substantially change conformation as the compression structure 102moves. This stiffness in a section of the flaps 108 can increase theclosure force applied to the wound 150.

The wound closure device 100 can be covered with a cover element thatcan be custom-designed to fit the shape of a particular patient. In someembodiments, the cover element can include a foam or other biocompatiblesubstance. The cover element may include prostheses or can be speciallydesigned to distribute force due to body weight or pressure to preventadverse wound events such dehiscence.

In some embodiments, a pump or other vacuum source can be used to applynegative pressure to the wound closure device 100. The pump can attachto the inlet 105 of the wound closure device 100. Additional vacuumsources can also be connected through an array of spaced inlets 105 inorder to spatially distribute the suction force so that the forceexerted on the compression structure 102 can be controlled separatelyfrom a fluid suction force. The amount of applied negative pressure canbe adjusted depending on the size and shape of the wound. Pressuresabove 125 mm to as much as 250 mm or more can be used to assist in woundclosure. The pressure can be reduced over time as the wound heals andreduces in size and depth. The vacuum source or pump can be furtherconnected in some embodiments with a surgical drain device as describedin greater detail below with reference to FIGS. 6, 11 and 12.

In accordance with various embodiments, the inlet(s) 105 can be disposedon an attachment plate 115. The attachment plate 115 may or may not berigid along certain directions and may be smooth on one or moresurfaces. The attachment plate 115 can overlay the compression structure102 and may also exhibit elastic or stretching properties. The materialof the attachment plate 115 can be biocompatible film such as thatprovided in conjunction with the Renasys® system available from Smith &Nephew. A preferred embodiment can also be used with a gauge as alsoprovided in the Renasys® system. The smooth attachment plate 115 enablesthe compression structure 102 to contract and expand freely withoutinterference from the underlying tissue, and without damaging theunderlying tissue. In a preferred embodiment, the attachment plate 115includes micropores that allow the passage of fluid through theattachment plate 115 and into the inlet 105 for removal from the woundsite. In some embodiments, the attachment plate 115 can contact a woundfilling material as described in greater detail below with reference toFIG. 6. In some embodiments, a drain or vacuum tube can extend throughthe attachment plate and into the wound filling material and/or to thesurgical drainage device as described in greater detail below withreference to FIGS. 11-12E.

In some embodiments, the micropores can have different sizes indifferent regions and/or can have different pore densities in differentregions in order to direct different force levels of the vacuum sourceto different regions of the device 100. Similarly, the compressionstructure 102 can be engineered with different internal cell sizesand/or cell densities to direct the distribution of forces from thevacuum source to different areas of the device 100.

The wound closure device 100 can be used without any sutures in caseswhere the skin edges on opposite sides of the wound 150 are sufficientlyaligned. Alignment of the skin can be facilitated by surgically trimmingthe wound margins in advance of closure. In other cases, sutures can beselectively utilized to better align the skin on opposite sides of thewound 150. In various embodiments, the device can be used to treat arange of extremities including legs, arms, fingers, toes, hands andfeet. After a period of healing, the device 100 can be removed andoptionally replaced with a smaller device.

As described briefly above, the peripheral edge 101 can be designed toimpart a greater lateral force 110 a than, for example, the lateralforce at a point 110 b within the wound closure device 100. Thisgradient of closure force as shown in FIG. 1 can ensure that the maximumdepth 150 a of the wound 150 experiences a greater force 110 a than theshallow depths 150 b of the wound 150 to sustain wound margin contactduring the application of negative pressure. It is desirable to have thewound margins initiate contact and healing at the deepest portion 150 aof the wound 150 and progress from the deepest portion 150 a to theshallowest portion 150 b such that the skin on opposite sides at thesurface of the wound 150 are the final portions of the wound margins toachieve closure. In many cases, the ends of the wound 105 undergo muchsmaller translation then the center. To accommodate this, thecompression structure 102 can be configured with larger cells in thecenter and smaller cells at the ends of the wound in some embodiments.

In some embodiments, a seal may be included on the flaps 108 or coverelement to seal the wound closure device 100 and prevent air fromentering or leaving the device while the pressure is changed inside,e.g., by application of negative pressure. The seal can include elasticsor adhesives to press a portion of the device 100 such as the peripheraledge 101 against the skin of the patient to produce an airtight seal. Incertain embodiments, the seal is included at the peripheral edge 101 ofthe wound closure device 100.

FIG. 2 shows the device of FIG. 1 shortly after negative pressure hasbeen applied at the inlet 105. The negative pressure can cause the cellsof the compression structure 102 to collapse in a preferred direction,e.g., length, width, or height. Due to the difference in forces 110 a,110 b at different positions with respect to the wound 150, the woundmargins on opposite sides at the deepest part 150 a of the wound 150move into proximity with one another. As the pressure continues to beapplied (FIG. 3), the wound margins continue to come into contact fromthe deepest portion 150 a to the shallowest portion 150 b of the wound150. Finally, after the negative pressure has been applied for sometime, the wound margins on opposite sides are fully in contact (FIG. 4).The closure of the wound 150 from the deepest point 150 a to theshallowest point 150 b promotes healing and prevents the development ofabscess or other pockets where bacteria can form. The wound closuredevice 100 can be left attached to the bodily extremity for an extendedtime period until wound healing is complete.

As shown in FIG. 5A, the compression structure 102 can have athree-dimensional geometry with cells 503 shaped as hexagons havinginternal membranes that can be arranged symmetrically or asymmetrically.In some embodiments, the cells 503 can include a plurality of polygonalshapes, irregular shapes, or both including, but not limited to,triangles, squares, parallelograms, pentagons, or any n-gon. In oneembodiment, the cells 503 of the compression structure 102 can be aportion of a truncated icosahedron (i.e., a soccer ball). The cells 503can be made of a pliable material.

In some embodiments, the interior of each cell 503 contains internalmembranes or walls 505 to enhance structural stiffness in one or moredirections. The internal membranes or walls 505 can be connected byhinged elements 506. As a result of this enhanced stiffness, the cells503 can preferentially collapse along a specific dimension (e.g.,length, width, or height) as shown in FIG. 5B. In accordance withvarious embodiments, a cell 503 can have a sufficient rigidity due tothe presence of internal membranes 505 that the cell does not expand ina direction perpendicular to the preferred axis of compression orcollapse. In some embodiments, this is accomplished through the use ofsingle- or double-hinging. The internal membranes 505 of adjoining cells503 can be oriented at different angles to accommodate the rotationalcomponent of the tissue movement during a wound closure procedure. Thesefeatures can apply to any wound shape in which the wound margins undergoa more complex movement (compared to the substantially one-dimensionallateral movement of the abdominal walls associated with abdominal woundclosure). Materials including structural elements, foam, tissue anchors,and operation of closure devices as described in International PatentApplication PCT/US2013/050698, filed Jul. 16, 2013, and U.S. patentapplication Ser. No. 13/365,615, filed Feb. 3, 2012, and also U.S.application Ser. No. 13/942,493 filed on Jul. 15, 2013, the entirecontents of the above-referenced applications being incorporated hereinby reference, can be used in conjunction with the devices and methodsset forth herein.

FIG. 5C illustrates a three-dimensional view of a wound closure device100 in accordance with embodiments of the present invention. Thedome-shaped device can be broken up into cells 503 having one or moreshapes as discussed above. In the embodiment of FIG. 5C, the cell shapeis triangular and the triangles tessellate to form hexagonal structures.FIG. 5D illustrates a portion of a structure such as the dome-shapeddevice of FIG. 5C. In some embodiments, the device can includeindividual cells 503 that are substantially flat and are joined to oneanother through the use of hinges 508. The hinges 508 can allow relativemovement and re-orientation of adjacent cells 503 to better conform thewound closure device 100 to a wound 150.

FIGS. 5E-5G are insets illustrating a portion of the wound closuredevice 100 indicated in FIG. 5A. In FIG. 5E, the walls between cells 503are in their typical extended form. When negative pressure is applied inthe device, the cells will contract in size as the wound margins beginto approximate as described above with reference to FIGS. 1-4. In someembodiments, the walls between cells 503 can include fold points atwhich the walls break or buckle to allow the cells 503 to contract insize as pressure is applied. The resulting walls upon folding areillustrated in top view in FIG. 5F and in perspective in FIG. 5G. Insome embodiments, a network of cells 503 is rigid enough to compress andprovide force to pull attached flaps 108. The flaps 108, in turn, cangenerate a force on attached tissue that surrounds the wound to providea force to close the deep portion of the wound before the shallowportion.

FIG. 6 illustrates a wound treatment system 600 including a woundtreatment device 100 that works in cooperation with additionalstructural and drainage features to accelerate wound healing inaccordance with various embodiments of the present invention. The system600 can include a surgical drain device 660 that attaches to the exposedwound surfaces in proximity to the deepest portion 150 a of the wound150. The surgical drain device 660 can include features and methodsdescribed in U.S. patent application Ser. No. 13/675,736, filed Nov. 13,2012, International Application PCT/US2012/033608 filed on Apr. 13,2012, and also in U.S. application Ser. No. 14/111,977 filed on Oct. 15,2013, the entire contents of the above applications being incorporatedherein by reference. The system 600 can also include a wound fillermaterial 670 such as collapsing structure with foam elements andoptionally including tissue anchors that attach to the wound marginsthat is placed in proximity to the shallow portion 150 b of the wound150.

The surgical drain device 660 can include apertures to allow woundmargins on opposite sides of the drain device 660 to come into contact.In some embodiments, the surgical drain device 660 has a plurality ofremovable drainage tubes that can be withdrawn from the device. Invarious embodiments, the surgical drain device 660 is made of abio-absorbable material such that the body of the device can be left inthe wound 150 without needing to be removed. The material 670 can beattached to the tube elements 675 such that removal of material 670 fromthe wound 150 will extract the tubes 675 from drain device 660. Thesurgical drain device is described in greater detail below withreference to FIGS. 11-12E. In some embodiments, the tubes 675 can besimilar to the plurality of drain tubes 30 as described below.

One embodiment of a cell framework for a compression structure 102according to the invention is shown in FIGS. 7A and 7B. As discussedabove, the compression structure 102 can have a curvature in onedimension (i.e., substantially cylindrical) or in two dimensions (i.e.,substantially spherical or dome-like). The cells 502 can include a firstset of x-y stabilizer elements 808 a and a second set of x-y stabilizerelements 808 b that are connected by a plurality of z-axis stabilizerelements 810. During collapse of the compression structure 102, therespective x-y stabilizer elements 808 a, 808 b are collapsible in thex-y directions, but the z-axis stabilizer elements 810 inhibit collapsein the z-direction. In preferred embodiments, the stabilizer elementscan articulate with respect to one another during collapse. The joints809 in the structure can be hinged or have a reduced thickness toaccommodate the flexing of the system. Note that the first, upper set ofstabilizer elements 808 a is longer than the second, lower set ofstabilizer elements 808 b. The flexures between the joints may also flexto accommodate the desired compression along a first, or lateral, axis117. Some expansion can occur along the second, or longitudinal, axis119 as the device compresses. The material of the compression structure102 can have a shape memory characteristic that, in combination with theforce due to negative pressure, defines the force level applied to thetissue. In some embodiments, the stabilizer elements 108 can include aplurality of stabilizing ribs, flexures or rods, made from a suitablyrigid or semi-rigid material, such as plastic. The spacing between theelements in the “open” state can be in a range of 1-2 cm, for example.In accordance with various embodiments, the first set of x-y stabilizerelements 808 a disposed on the outermost surface of the compressionstructure 102 can have longer segment lengths than the second set of x-ystabilizer elements 808 b disposed on the innermost surface of thecompression structure 102. In different embodiments, the first set ofx-y stabilizer elements 808 a disposed on the outermost surface of thecompression structure 102 can have a larger or equal radius of curvaturethan the second set of x-y stabilizer elements 808 b disposed on theinnermost surface of the compression structure 102.

In another embodiment, shown in FIGS. 8A and 8B, the cells of thecompression structure 102 can include truss stabilizers 812 to inhibittilting of the structure 102 during collapse. The truss stabilizers 812keep the upper 808 a and lower 808 b x-y stabilizers aligned with oneanother as the compression structure 102 collapses. In some embodiments,the truss stabilizers 812 can be rigid in certain directions andrelatively less rigid in other directions (for example, the trussstabilizer can be bowed) to promote collapse in certain directions. FIG.8C illustrates an alternative embodiment having truss stabilizers 812 inan “x”-shaped pattern.

The cells 502 in certain embodiments can be made, in whole or in part,from a shape memory material. Various shape memory materials can be usedwhich return from a deformed state (temporary shape) to their original(permanent) shape. This change in shape can be induced by an externalstimulus or trigger. In one embodiment, the original or “permanent”shape of the wound closure device is the “collapsed” configuration. Whenthe wound closure device is initially applied at the wound, the devicecan be deformed in a temporary expanded state. The device canpreferentially revert to its original or “collapsed” state or,alternatively, cause the device to first expand to engage the tissue.The “collapse” force of the shape memory structure can be in addition toor an alternative to the vacuum force induced by the negative pressuresource. In certain embodiments, the application of a negative pressureto the wound closure device can cause the device to revert to itsoriginal state.

FIG. 9 illustrates an enlarged view of a preferred embodiment of atissue anchor system 400 in accordance with some aspects of theinvention. One side of the flaps 108 can have a first group of anchorelements 404 that are adapted to grasp the wrap 406 and/or the tissue.The first anchor elements 404 can be shaped to grasp the wrap 106 suchas with a distal hooked shape 406. As the flaps 108 attach to the wrap106 with a certain grasping strength in order to sufficiently affix thewound closure device to the bodily extremity, a specified force level Fmust be applied to remove the anchor elements 404 from the wrap 408 thatexceeds the pulling force being applied to the device 100.

In some embodiments, the flaps 108 can attach at least in part to thetissue of a patient including dermal tissue. As the tissue to be graspedby the flaps 108 has different structural characteristics then the wrap106, a second group of anchor elements can be adapted to grasp tissueand can have a different shape and grasping force then the first anchorelements 404. As discussed in greater detail below, barbs can havebilateral prongs that tend to collapse upon insertion in tissue and yetexpand when pulled in an opposite direction such that a certain pullingforce can be applied to tissue as the compression structure 102collapses. However, the prongs or cone shape anchor element can have arelease force such that the barbs can be manually pulled from the tissuewithout causing injury. In some embodiments, the flaps 108 attach toboth tissue and the wrap 106.

The characteristics of the anchors, and their resulting force profiles,can vary by a number of parameters, such as the length of the anchor,the shape of the anchor, the structure of grasping features, thematerial(s) used for the anchor, the relative flexibility/rigidity ofthe anchors, and the spacing/density of the anchors. FIG. 10 illustratesthree examples of different types of grasping features, including abarbed configuration 605, a staggered hook configuration 606, and astaggered barbed configuration 607. The anchoring process can beaugmented by the application of a seal as described above. The forceprofile can also be varied by controlling the vacuum force distributionin the compression structure 102, such as by varying the cell sizeand/or cell density of the compression structure 102.

FIG. 11 schematically depicts a surgical drain device 660 andaccompanying support equipment for drainage of at least a portion of awound. The surgical drain device 660 can have a plurality of drain tubes30 attached to an adhesion matrix 25 and configured so as to drain thefull extent of the portion of the wound. The drain tubes 30 can beconnected at their proximal ends to a manifold 40 that can in turn beconnected through vacuum tubing 50 to a vacuum pump 130 or other vacuumsource. Fluid 125 drained from the wound can be optionally accumulatedin fluid trap 120. In some embodiments, the vacuum tube 50 and manifold40 connect to a valve or port in the wound filler material 670. In thisembodiment, removal of the wound filler material 670 (i.e., at the endof a wound closure operation) can release the manifold 40 and attachedplurality of drain tubes 30 from the surgical drain device 660. Theadhesion matrix 25 can be made of a bioabsorbable material and may beleft in the body once the drain tubes 30 have been removed. Vacuum pumpor other vacuum source 130 can include one or more electronic devices,such as a microprocessor with memory and software, to monitor the vacuumlevel, pneumatic resistance, and/or fluid removal amount or rate. Theelectronic device(s) also can be used to control the operation of thesystem over time according to user-defined parameters, according to apreset program, or in response to data collected on vacuum, resistance,and/or fluid removal.

The number of drain tubes in the surgical drain device 660 can varydepending upon the needs of the device, including the amount of fluid tobe drained and the size of the wound and shape of the device. Typically,the device will contain from 2 to about 20 drain tubes. In a preferredembodiment, the device contains preferably at least 3 tubes, and forlarger areas from about 5 to about 12 tubes.

The drain tubes 30 can be fabricated from any biocompatiblethermoplastic or thermoset material. Examples include surgical gradesilicone rubber, polyurethane, polyamide, polyimide, PEEK (polyetherether ketone), polycarbonate, PMMA (polymethylmethacrylate), andpolyvinylchloride. The drain tubes 30 are intended to be removed afterfluid build-up has reduced to a level that is stable without drainage.However, in an alternative embodiment, the drain tubes 30 can be made ofa biodegradable material and can be left in place. The drain tubes 30can be flexible so as to conform to the tissues surrounding the deviceand to accommodate movement of the patient without causing discomfort.The drain tubes can be open ended or close ended. In a preferredembodiment, the drain tubes are close ended and possess apertures orholes along their length for the uptake of fluid.

FIGS. 12A-E show several embodiments of the adhesion matrix 25. Aportion of the adhesion matrix 25 between two neighboring drain tubes 30and drain channels 35 is shown. The embodiment shown in FIG. 12A has aregular arrangement of rectangular apertures 27 to allow tissue contactthrough the device. This tissue contact enables a faster healing rate atthe apertures 27. Circular apertures are shown in FIG. 12B. Theembodiment of FIG. 12C includes apertures 27 that are formed intolateral channels. Fluid flows laterally through these channels towardopenings 36 in the drain tube channels 35, drawn by the reduced pressurein the drain tubes 30. As shown in FIGS. 12D and 12E, the surfaces ofthe adhesion matrix, including the drain channels, can be endowed withan array of hooks or barbs to promote anchoring of the device toadjacent tissues. In the embodiment shown in FIG. 12E, the hooks on theupper side 28 are longer than the hooks on the lower side 29. Thisarrangement can be used where the tissues on either side of the deviceare of different density. For example, longer hooks such as about 1.5 toabout 3 mm in length are preferred for less dense tissue, such assubcutaneous fat tissue, whereas shorter hooks such as about 0.5 toabout 1.5 mm in length are preferred for denser tissues such as fasciaand muscle.

The adhesion matrix 25, including any drain tube channels 35 and hooksor barbs, can be fabricated from a biodegradable polymer material, asthese structures are intended to remain in place in the patient's bodyafter removal of the drain tubes 30, so as not to disrupt the healingprocess. Examples of suitable biodegradable or resorbable materialsinclude Vicryl (polyglycolic acid), Monocryl (glycolicacid-ε-caprolactone copolymer), PDS (polydioxanone, PDO), PLA(polylactic acid, polylactide), PLLA (poly-L-lactic acid), PDLA(poly-D-lactic acid), PGA (polyglycolic acid, polyglycolide), PLGA(poly(lactic-co-glycolic acid)), PHB (polyhydroxybutyrate), and PCL(polycaprolactone). In a preferred embodiment, the adhesion matrix 25,including any drain tube channels 35, is formed of an open network ofpolymer chains that has sufficient porosity to allow infiltration bycells and fluid flow across the material. Cellular infiltration canpromote tissue adhesion and the biodegradation of the polymer after thewound has healed. In some embodiments, the adhesion matrix 25 includingany drain tube channels 35 is permeable to seroma fluid but notpermeable to cells. In other embodiments, the adhesion matrix 25,including any drain tube channels 35, is permeable to fluid andelectrolytes but is impermeable to proteins. The permeability propertiesof the matrix polymer material that makes up the basic substrate of theadhesion matrix 25 can be the same or different compared to the materialthat makes up the drain tube channels 35. In a preferred embodiment, thepolymer chains, or fibers composed of polymer chains, of the adhesionmatrix 25 are aligned along an axis substantially perpendicular to theaxes of the nearest drain tubes 30. This alignment pattern promotes theflow of fluid through or along the surface of the adhesion matrix 25towards the drain tubes.

The adhesion matrix 25, and thus the overall drain device 660, can haveany form suitable for insertion into the wound or seroma where it is tobe inserted. Generally, the form is that of a thin sheet or flexibleplanar mesh having an essentially rectangular shape. However, the shapecan be rounded, circular, elliptical, oval, or irregular. Preferably thecorners are rounded so as to minimize mechanical irritation ofsurrounding tissues. The size of the device is also determined by theparticular use and anatomy of the patient. For example, the adhesionmatrix can have an overall width and length in the range from about 2 cmto 25 cm, such as about 10 cm×12 cm or about 20 cm×25 cm. The thicknessof the adhesion matrix 25 can be from about 0.5 mm to about 1 cm; wherethe sheet of material is preferably less than 5 mm in thickness andpreferably the adhesion matrix 25 is about 1-2 mm thick. The thicknessof the entire drain device 660, including the sheet of the adhesionmatrix 25, drain tubes 30, and any hooks or glue pads is about 5 mm orless, 10 mm or less, or about 5-10 mm.

The adhesion matrix 25 can be coated with an adhesive material such assurgical glue either in addition to or instead of using hook or barbstructures that stabilize tissue layers on either side of the draindevice. Any type of surgical adhesive suitable for use within the bodycan be used, including polyethylene glycol polymers, adhesive proteins,gelatin-thrombin mixtures, albumin-glutaraldehyde, and fibrin-basedsealants. Cyanoacrylates are to be avoided, as they cause inflammationif used internally. An adhesive coating can be placed on one or bothsurfaces of the adhesion matrix 25. Adhesive coatings can be applied tothe device prior to its placement in a patient, i.e., as part of thedevice fabrication process. An adhesive coating can cover all or aportion of a surface of the device 660. A surgical adhesive can be usedin the form of a fibrous mat or pad that is soaked or coated with anadhesive composition. The mat or pad is preferably fabricated from abiodegradable polymer, such as the type used to prepare the adhesionmatrix 25. One or more layers of adhesive material can be placed betweenthe device and surrounding tissue at the time of placement in thepatient.

When the wound closure device 100 containing the compression structure102 is applied to a wound 150 and negative pressure is applied, thewound margins will begin to approximate beginning with the deep portionof the wound 150 a. As the wound margins rotate towards one another, thecompression structure 102 must also compress along the lateral direction117. Compression or collapse of the compression structure 102 can beachieved by several methods. FIGS. 13A-13F illustrate an embodiment of aportion of a compression structure 102 as it collapses in size. Thecompression structure 102 is depicted in an unstressed, expanded statein FIGS. 13A (end view) and 13D (top cross-sectional view). In someembodiments, the expanded state may be the natural resting state of acompression structure 102. In the expanded state, the rigid orsemi-rigid membranes 109 can be substantially perpendicular to the cellwalls 107. In FIGS. 13B and 13E, the portion of the compressionstructure 102 is depicted in an intermediate state of collapse. Inaccordance with various embodiments, the membranes 109 can be joined tothe walls 107 using hinges or any other attachment method that allowsthe membranes 109 to rotate or pivot with respect to the walls 107. Thecompression structure 102 is depicted in the collapsed state in FIGS.13C and 13F. In some embodiments, the walls 107 of the compressionstructure 102 re-orient from a fan- or V-shape as seen in an end view tobeing substantially parallel in the compressed state. This rotation ofthe walls 107 mirrors the rotation of the wound margins as they begin toapproximate during closure and healing of the wound 150.

FIG. 13G illustrates a portion of a compression structure 102 includingrigid or semi-rigid membranes 109 and walls 107 in accordance withvarious embodiments of the present invention. In accordance with variousembodiments, the membranes 109 can include multiple interlockingsections such as an inner sliding section 109 b and an outer slidingsection 109 a as shown in FIGS. 13H and 13I. In some embodiments, theinner sliding section 109 b can be configured to fit partially or whollywithin an adjacent outer sliding section 109 a. In a first, extendedstate as shown in FIG. 13H, the inner sliding section 109 b is withdrawnfrom the outer sliding section 109 a to provide the maximum possibleextension. As the compression structure 102 compresses, the innersliding sections 109 b will gradually slide into the body of the outersliding sections 109 a as shown in FIG. 13I. In some embodiments, theinner sliding section 109 b can slide within an outer sliding section109 a until an adjoining wall 107 prevents further sliding. Theresulting reduction in the total length of the membranes 109 is depictedin FIG. 13J.

FIG. 14 illustrates a cross-section of a wound closure device 100applied at a body extremity to a wound 150 caused by amputation. Thewound closure device 100 can include a collapsible structure 102, aninlet 105, and a drape 118. The wound closure device 100 can have adome-shaped geometry in order to extend around the limb in such a waythat the peripheral edge of the dome fully surrounds the wound. When anegative pressure is applied to the inlet 105, the collapsible structure102 and drape 118 can apply a force to the wound 150 that is strongestat the deepest point of the wound 150 a. The collapsible structure 102in combination with the application of negative pressure can exert aforce on the wound 150 to facilitate closure of the wound 150 beginningwith the deep portion of the wound 150 a.

Although the wound closure device 100 is described as having a domeshape (i.e., a curvature along two axes), it is also contemplated thatembodiments of the present invention can have curvature in only onedimension (i.e., a cylindrical geometry). As a non-limiting example, awound closure device 100 in accordance with the present disclosure cancover a wound on a lateral surface of a bodily limb or extremity such asthe thigh. The device can have a range of values of curvature toaccommodate wounded extremities as varied as fingers or toes to legs orarms. In some embodiments, the radius of curvature 116 of a portion ofthe device (R_(C2)) is different from the radius of curvature 156 of thetissue (R_(C1)) under treatment such that, as a result, the device is atleast partially spatially separated from the tissue surface.

The wound 150 can have a width (X) 152 and a depth (Y) 154. In someembodiments, the depth 154 of the wound 150 can be between 0.1 and 1times the width 152 of the wound 150. Previously available treatmentsmay incompletely treat wounds with such large aspect ratios of depth towidth because they typically force the margins of the wound at a shallowportion 150 b of the wound to approximate (i.e., come into contact)before the margins of the wound at a deep portion 150 a of the wound. Inthe case where the shallow margins approximate first, the potentialarises for seroma formation or infection of the wound below the surface.Embodiments of the present invention can ameliorate this problem bypreferentially applying a greater lateral force 110 a at the deepportion 150 a of the wound 150 than at the shallow portion 150 b of thewound as will be described in more detail below. In accordance withvarious embodiments, a portion 114 of the wound closure device 100 canbe positioned over tissue adjacent to the wound 150. In someembodiments, the length of the portion 114 adjacent to the wound 150 canbe 0.4 to 0.8 times the depth 154 of the wound 150.

The collapsible structure 102 can be situated outside of the wound asshown in FIG. 1A and can have a number of cells 103 separated by rigidor semi-rigid membranes 107 that are hinged together at joints. Theshape of the cells 103 can be selected based on the shape of the wound150. Details on the cell shape and composition will be described ingreater detail below with reference to FIG. 5. The collapsible structure102 can be pre-stressed to exert a compression force on the wound 150 tomore quickly bring the wound margins together. Certain elements or cellsof the collapsible structure can have greater compliance to enableinterdigitated collapse. In some embodiments, the collapsible structure102 can include a circle or spiral format that lays flat in or above thewound to achieve a similar collapsing effect. In various embodiments,the collapsible structure 102 can be symmetrical or asymmetrical. As thecollapsible structure collapses, the outermost surface of thecollapsible structure 102 can have a larger radius than the innermostsurface of the collapsible structure 102. Note that the walls ofadjoining cells extend at different angles due to the arced shape of thedevice that is needed to extend over the wound. For amputation wounds,the device must have a dome-shaped structure to enclose the woundopening at one end of the limb. The collapsible structure can have acurved contour that extends over at least a portion of tissue adjacentto the wound or wound opening. As described above with reference toFIGS. 13A-J, the collapsible structure can include articulating elementsthat undergo rotational movement during closure of the wound marginswithin a wound such as an amputation wound. In some embodiments, thearticulating elements can rotate at joints such that the collapsiblestructure collapses along a curved path above the wound opening.

The collapsible structure 102 can include rigid or semi-rigid membranes109 connecting walls 107 between cells 103. The lower set of membranes109 can form a surface having a smaller radius of curvature 116 than theradius of curvature 156 of the surface of the tissue proximate to thewound. In some embodiments, the smaller radius of curvature is enforcedby stiffened or firm elements within the collapsible structure 102. Thedifference in the radius of curvature 116 of the collapsible structure102 relative to the radius of curvature of the tissue surface can impartadditional force at the lateral ends of the collapsible structure 102.In some embodiments, the firmness or stiffness of the radius ofcurvature of the collapsible structure 102 can help allow the structureto resist buckling when a negative pressure is applied at the port 105.In some embodiments, the collapsible structure 102 can include a lateralportion that can apply an inward force to the deep portion 150 a of thewound 150 to cause the deep portion 150 a to close before the shallowportion 150 b. In accordance with various embodiments, the collapsiblestructure 102 can contact the portion of the tissue adjacent to thewound opening and can include a stiff edge.

The drape 118 can provide a leak-free seal between the wound closuredevice 100 and the tissue surface. In some embodiments, the drape 118can be made from materials including plastics or tapes and furtherincluding biocompatible materials. In some embodiments, the drape 118can include adhesives or surgical glues as described above withreference to the adhesion matrix 25. The drape 118 can improve sterilityof the wound 150 during healing by preventing ingress of dirt orbacteria. In some embodiments, the drape 118 can affix a lateral portionof the collapsible structure 102 to tissue surrounding at least the deepportion 150 a of the wound 150.

The wound closure device 100 can be covered with a cover element thatcan be custom-designed to fit the shape of a particular patient. In someembodiments, the cover element can include a foam or other biocompatiblesubstance. The cover element may include prostheses or can be speciallydesigned to distribute force due to body weight or pressure to preventadverse wound events such dehiscence.

In some embodiments, a pump or other vacuum source can be used to applynegative pressure to the wound closure device 100. The pump can attachto the inlet 105 of the wound closure device 100. Additional vacuumsources can also be connected through an array of spaced inlets 105 inorder to spatially distribute the suction force so that the forceexerted on the collapsible structure 102 can be controlled separatelyfrom a fluid suction source. The amount of applied negative pressure canbe adjusted depending on the size and shape of the wound. Pressuresabove 125 mm to as much as 250 mm or more can be used to assist in woundclosure. The pressure can be reduced over time as the wound heals andreduces in size and depth. The vacuum source or pump can be furtherconnected in some embodiments with a surgical drain device as describedin greater detail above with reference to FIGS. 6, 11 and 12.

In accordance with various embodiments, the inlet(s) 105 can be disposedon an attachment plate 115. The attachment plate 115 may or may not berigid along certain directions and may be smooth on one or moresurfaces. The attachment plate 115 can overlay the collapsible structure102 and may also exhibit elastic or stretching properties. The materialof the attachment plate 115 can be biocompatible film such as thatprovided in conjunction with the Renasys® system available from Smith &Nephew. A preferred embodiment can also be used with a gauge as alsoprovided in the Renasys® system. The smooth attachment plate 115 enablesthe collapsible structure 102 to contract and expand freely withoutinterference from the underlying tissue, and without damaging theunderlying tissue. In a preferred embodiment, the attachment plate 115includes micropores that allow the passage of fluid through theattachment plate 115 and into the inlet 105 for removal from the woundsite. In some embodiments, the attachment plate 115 can contact a woundfilling material as described in greater detail above with reference toFIG. 6. In some embodiments, a drain or vacuum tube can extend throughthe attachment plate and into the wound filling material and/or to thesurgical drainage device as described in greater detail above withreference to FIGS. 11-12E.

In some embodiments, the micropores can have different sizes indifferent regions and/or can have different pore densities in differentregions in order to direct different force levels of the vacuum sourceto different regions of the device 100. Similarly, the collapsiblestructure 102 can be engineered with different internal cell sizesand/or cell densities to direct the distribution of forces from thevacuum source to different areas of the device 100.

The wound closure device 100 can be used without any sutures in caseswhere the skin edges on opposite sides of the wound 150 are sufficientlyaligned. Alignment of the skin can be facilitated by surgically trimmingthe wound margins in advance of closure. In other cases, sutures can beselectively utilized to better align the skin on opposite sides of thewound 150. In various embodiments, the device can be used to treat arange of extremities including legs, arms, fingers, toes, hands andfeet. After a period of healing, the device 100 can be removed andoptionally replaced with a smaller device.

In many cases, the ends of the wound 105 undergo much smallertranslation then the center. To accommodate this, the collapsiblestructure 102 can be configured with larger cells in the center andsmaller cells at the ends of the wound in some embodiments.

The wound closure device 100 can also include a compression element 121such as a clamp to increase the amount of force applied at the deepportion 150 a of the wound. In some embodiments, the compression element121 can include only discrete points of contact around the wound such aswith a surgical clamp or distractor or can surround the wound at allsides such as with an elastic band. In some embodiments, the compressionelement 121 can include a tacky or rubberized surface or an adhesive toimprove contact with the tissue and prevent relative movement of thecompression element 121 over the tissue surface during wound closure.

Some types of incisions and wounds are characterized by a greater areaat the base (i.e., the deepest portion) of the wound than at the skinsurface. FIG. 15A illustrates a cross-section of such a wound, which maybe a pressure ulcer, a sacral decubitus ulcer, or an ischial decubitusulcer in some embodiments. Such a wound could also be generated bydrainage of a fluid-filled cavity such as an abscess or seroma. Theinset wound 1610 is characterized by overhanging skin flaps 1604 thatare undermined by a portion of the wound volume 1612. The underminedportion of the wound volume 1612 may create an especially difficultbarrier to healing because of the risk of seroma or bacterial infectionshould the surface portion of the wound close before the margins in thehidden portion are properly closed. Due to the location and orientationof some ulcers of this type, the inset wound 1610 can lie in a concavityin the tissue 1600 with respect to high points 1602 surrounding theinset wound 1610. As a result, typical surgical dressings applied to thewound cannot apply sufficient pressure on the wound surface to effectproper drainage or to encourage the margins of the inset wound 1610 atthe surface and in the undermined portion 1612 to properly approximate.

FIG. 15B illustrates a wound closure device 1000 that can be applied toan inset wound 1610 in accordance with various embodiments of thepresent invention. The wound closure device 1000 can include acompression element such as a bladder 1010, a drape 1050, an inlet 105,and a porous stem 1020. The wound closure device 1000 can be placedwithin the inset wound 1610. When negative pressure is applied at theinlet 105 as shown in FIG. 15C, the device 1000 can conform to thesurface of the tissue 1600 and provide compressive force to the skinflaps 1604 to create apposition of the wound tissue under the skin flipsand at the base of the wound. In some embodiments, additionalcompressive force can be generated by inflating or filling thecompression element. By forcing the wound margins into apposition, thewound margins can approximate more quickly and can close off theundermined portion 1612 before approximation and closure occurs at theskin surface. An exemplary application of a wound closure device 1000 tobring the margins in the undermined portion into opposition is shown inFIG. 15D.

FIG. 15E illustrates a cross-sectional view of a wound closure device1000 that includes a surgical drain device 660 in accordance withvarious embodiments of the present invention. The stem 1020 of the woundclosure device 1000 can be in contact with at least a portion of thesurgical drain device 660. As described above with reference to FIGS. 6and 9-12E, the surgical drain device 660 can include apertures 27 toallow wound margins on opposite sides of the drain device to come intocontact through the device. In some embodiments, the surgical draindevice 660 can include drain tubes 30 to carry fluid from the wound 1610to the stem 1020. In some embodiments, the drain tubes 30 can beattached to the stem 1020 or another element of the wound closure device1000 and can be removed from the surgical drain device 660 when thewound closure device 1000 is removed from the wound 1610. In someembodiments, the surgical drain device 660 can include drain channelsthat are coupled to the stem 1020 to allow fluid to be drawn to the stem1020 and out of the wound cavity.

In some embodiments, the surgical drain device 660 can include tissueanchors 440 as described previously. The tissue anchors 440 can attachto the wound margins on the underside of the skin flaps 1604 and at thebase of the wound. In some embodiments, the tissue anchors 440 canimprove approximation of wound margins that, due to tissue inelasticityor wound geometry, simply cannot stretch enough to meet under pressurefrom the bladder 1010.

In accordance with various embodiments, the stem 1020 can be acollapsible element that can collapse in both the horizontal andvertical directions (i.e., the depth and lateral directions according tothe wound geometry). As negative pressure is applied, the stem 1020 cancollapse in the vertical direction to allow wound margins in theundermined portion 1612 of the wound 1610 to approximate. The stem 1020can also collapse in the horizontal direction to allow the wound marginsin the surface portion of the wound (i.e., the skin flaps 1604) toapproximate. In some embodiments, the stem 1020 can contain acollapsible structure as described above with reference to previousembodiments.

FIG. 16A shows a perspective view of a wound closure device 1000 inaccordance with various embodiments of the present invention. Inaccordance with various embodiments, the device 1000 can include acompression element such as a bladder 1010, a porous stem 1020, a port1012, and a pressure sensor 1014.

The bladder 1010 of the wound closure device 1000 can be made of anysuitable material including, but not limited to, plastics, rubbers, orfabrics. The bladder 1010 can have a level of malleability andcompliance such that it can mold to fill irregularities across a tissuesurface. In some embodiments, the bladder 1010 may be filled with air orother gases, liquids such as saline, or colloidal materials such as gelsor foams. In some embodiments, the bladder can be inflated byintroducing filler material through the port 1012. As a non-limitingexample, the bladder 1010 can be filled by a pump such as a hand- orbattery-operated portable pump. One skilled in the art will appreciatethat other methods of filling the bladder 1010 are also contemplated asbeing within the scope of the present invention including in-house andother stationary pressure sources, mouth-blowing, and integrated pumpsor micro-pumps mounted within or on the bladder 1010. In someembodiments, the pressure within the bladder 1010 can be adjusted by thepatient. In some embodiments, the bladder 1010 can include an integratedor detachable pressure gauge to measure the level of pressure within thebladder 1010.

The porous stem 1020 can be made of any suitable material including, butnot limited to, biocompatible foam or gauze. In accordance with variousembodiments, the porous stem 1020 can compress as negative pressure isapplied as shown in the transformation of the stem between FIGS. 15B and15C. The porosity of the stem 1020 can allow fluids to be drawn upwithin or through the stem 1020 to facilitate drainage of the wound1610.

As with most wounds, an inset wound 1610 may be sensitive to the appliedpressure. If the applied pressure is too great, adverse healing mayensue due to restricted blood flow or other causes. The pressure sensor1014 can detect the magnitude of the applied force on the tissue at thesurface of the skin. In some embodiments, the pressure sensor 1014 maybe connected to the inlet 1012 to relieve overpressure within thebladder 1010 when the level of pressure on the tissue surface is toohigh.

When applied to a wound 1610, the wound closure device 1000 can includea drape 1050 to create a leak-free seal between the wound closure device1000 and the surface of the tissue 1600. In some embodiments, the drape1050 can be made from materials including plastics or tapes and furtherincluding biocompatible materials. In some embodiments, the drape 1050can include adhesives or surgical glues as described above. The drape1050 can improve sterility of the wound 1610 during healing bypreventing ingress of dirt or bacteria. In some embodiments, the drape1610 can extend from the wound 1610 to beyond at least the high points1602 of the surrounding tissue surface. In some embodiments, the drape1050 includes an inlet 105 through which negative pressure may beapplied to the wound closure device 1000.

FIG. 16B illustrates a cross-sectional view of a wound closure device1000 having a shell 1015 in accordance with various embodiments of thepresent disclosure. In various embodiments, the shell 1015 can be aseparate external element attached to the bladder 1010 or can beintegrated within the bladder 1010. The shell 1015 can be made ofunyielding, firm, or rigid materials such that it holds its shape and isnot pliable like the remainder of the bladder 1010. When negativepressure is applied to the device 1000, the drape 1050 will pull tautagainst the shell and apply pressure downward. Because of the rigidityof the shell 1015, the applied pressure will be primarily directed intothe tissue 1600 (rather than into reshaping the bladder 1010) andthereby increase the overall force that can be applied to the skin flaps1604 for the same level of negative pressure as compared to a device1000 having no shell 1015.

FIG. 16C illustrates a cross-sectional view of a wound closure device1000 with a drain tube 1024 that passes through the bladder 1010. Analternative location of a drain tube 1026 is shown in FIG. 16D. In thisembodiment, the drain tube 1026 passes below the bladder 1010 and beyondthe bladder's periphery. In some embodiments, a pump can be connected tothe drain tube 1024, 1026 to extract accumulated fluids via the porousstem 1020. In some embodiments, the drain tubes 1024, 1026 can beconnected with the inlet 1012 to allow a single source of negativepressure to extract accumulated fluids and to create negative pressurewithin the wound closure device 1000.

FIG. 16E illustrates an embodiment of a modular bladder 1010 inaccordance with various embodiments of the present invention. Themodular bladder 1010 may be made of individual sections 1011 separatedby seams 1017. In some embodiments, the modular bladder 1010 may be cutor torn along the seams to remove sections 1011 until the desiredbladder size is achieved. In accordance with various embodiments, eachbladder section 1011 may be individually inflatable or fillable toprovide different levels of pressure at different points on the bladder1010. Although the modular bladder 1010 is depicted as having a grid ofsquare sections, it is also contemplated that the modular bladder couldinclude concentric ring sections, tessellating sections having othershapes than rectangles, or any other suitable shape as dictated byapplication-specific needs. In some embodiments, the seams 1017 can beself-sealing or self-healing such that each section 1011 becomes orremains pressurized or filled upon cutting or tearing at the seams 1017.

FIG. 17 illustrates an exemplary methodology 1200 for wound healing andclosure in accordance with various embodiments of the present invention.In step 1202, an open wound at a body region having a depth including adeep portion and a shallow portion is surgically prepared for negativepressure wound therapy. For example, the open wound can be an amputationwound in a body region such as an amputated limb. A wound closure deviceis configured that includes a collapsible compression structure for thewound opening (step 1204). The configured wound closure device has asize and shape that conforms to the wound opening. The wound closuredevice is placed over the open wound (step 1206). Negative pressure isapplied at a port or inlet to cause the compression structure to atleast partly collapse (step 1208). The collapse of the compressionstructure causes the deep portion of the wound margins to close beforethe shallow portion. The wound closure device can optionally be removedand a second wound closure device can be applied to the wound (step1210). The wound closure device can be removed, and the wound closurecan be completed with or without sutures (step 1212).

FIG. 18 illustrates an exemplary methodology 1400 for wound healing andclosure in accordance with various embodiments of the present invention.A wound in a tissue that has a depth including a deep portion and ashallow portion is surgically prepared for negative pressure woundclosure therapy (step 1402). A wound closure device including acollapsible structure, flaps, and a port or inlet is configured (step1404). The collapsible structure has a radius of curvature. Optionally,a surgical drain device is placed into the wound. The wound closuredevice is placed over the wound in the tissue (step 1406). A surface ofthe tissue surrounding the sound defines a radius of curvature that isgreater than the radius of curvature of the collapsible structure. Thetissue is optionally compressed on opposite sides of the wound while thewound closure device is attached to tissue surfaces surrounding thewound (step 1408). Negative pressure is applied at the inlet to causethe collapsible structure to at least partly collapse (step 1410). Thecollapse of the collapsible structure causes the deep portion of thewound to close before the shallow portion. The wound is drained offluids during movement of the wound margins (step 1412). The woundclosure device is removed from the wound, and the wound is closed withor without sutures (step 1414).

FIG. 19 illustrates an exemplary methodology 1500 for wound healing andclosure in accordance with various embodiments of the present invention.A wound that includes an undermined portion and a surface portion issurgically prepared for negative pressure wound therapy (step 1502). Awound closure device is configured including a compression device, adrainage element, and a port or inlet (step 1504). For example, thecompression device can be a bladder 1010 as described previously herein.The wound closure device is placed into the wound (step 1506). Negativepressure is applied at the inlet to cause the bladder to exert pressureon a surface of the tissue (step 1508). The pressure exerted by thebladder causes the undermined portion of the wound to close before thesurface portion. The wound is drained of fluids through the drainageelement during movement of the wound margins (step 1510). The woundclosure device is removed from the wound, and the wound is closed withor without sutures (step 1512).

FIG. 20 illustrates an exemplary methodology 1700 for wound healing andclosure in accordance with various embodiments of the present invention.A wound in a tissue that includes an undermined portion and a surfaceportion is surgically prepared for negative pressure wound therapy (step1702). A wound closure device including a compression device, a drainageelement, and a port or inlet is configured (step 1704). The drainageelement is collapsible in the horizontal and vertical directions. Anexemplary compression device can include a bladder 1010 as describedpreviously herein. A surgical drain device is configured (step 1706).The surgical drain device and the wound closure device are placed intothe wound (step 1708). The surgical drain device is placed ahead of thewound closure device and the surgical drain device and wound closuredevice are in contact after placement. Negative pressure is applied atthe inlet to cause the compression device to exert pressure on the woundand a surface of the tissue surrounding the wound (step 1710). Thepressure exerted by the compression device collapses the drainageelement of the wound closure device in the vertical and horizontaldirections to approximate wound margins in the undermined portion andwound margins at the surface portion, respectively. The wound is drainedof fluids during movement of the wound margins (step 1712). The woundclosure device is removed from the wound, and the wound is closed withor without sutures (step 1714). A portion of the surgical drain deviceremains in the closed wound.

While the present inventive concepts have been described with referenceto particular embodiments, those of ordinary skill in the art willappreciate that various substitutions and/or other alterations may bemade to the embodiments without departing from the spirit of the presentinventive concepts. Accordingly, the foregoing description is meant tobe exemplary and does not limit the scope of the present inventiveconcepts.

A number of examples have been described herein. Nevertheless, it shouldbe understood that various modifications may be made. For example,suitable results may be achieved if the described techniques areperformed in a different order and/or if components in a describedsystem, device, or method are combined in a different manner and/orreplaced or supplemented by other components or their equivalents.Accordingly, other implementations are within the scope of the presentinventive concepts.

1. A negative pressure wound closure device to treat a wound comprising;a collapsible structure positionable external to a wound opening, thecollapsible structure having a curved contour that extends over at leasta portion of tissue adjacent to the wound opening, the collapsiblestructure having articulating elements that are displaced duringmovement of spaced apart wound margins within the wound opening; and aport on or adjacent to the collapsible structure that is connectable toa negative pressure source such that a negative pressure is applied toremove fluid from the wound opening and impart a force to the spacedapart wound margins operable to move the wound margins to a more closedposition.
 2. The device of claim 1 further comprising a flap having afirst portion and a second portion.
 3. The device of claim 2 wherein thefirst portion is relatively more elastic than the second portion.
 4. Thedevice of claim 1 wherein the flaps are attached to a wrap using a firstplurality of anchoring elements.
 5. The device of claim 1 wherein thecollapsing structure further comprises a compression element thatcontacts the portion of tissue adjacent the wound opening including astiff edge.
 6. The device of claim 1 further comprising a drape thataffixes a lateral portion of the structure to tissue surrounding atleast a deep portion of the wound.
 7. The device of claim 6 wherein theforce on the deep portion is greater than the force on a shallowportion.
 8. The device of claim 7 wherein the negative pressure appliedcauses the structure to at least partially collapse and causes thelateral portion to apply an inward force to the deep portion of anamputation wound to close before the shallow portion.
 9. The device ofclaim 1 wherein a radius of curvature of the structure is different froma radius of curvature of the tissue surrounding the wound.
 10. Anegative pressure wound closure device to treat an amputation woundcomprising: a collapsible structure positionable external to anamputation wound, the collapsible structure having articulating elementsundergoing rotational movement during closure of wound margins withinthe amputation wound; a negative pressure source in fluid communicationwith a wound cavity within the amputation wound such that fluid isremoved from the wound cavity and wherein a compressive force isimparted to tissue on at least a portion of tissue adjacent to the woundopening that is coupled to the collapsible structure.
 11. The device ofclaim 10 further comprising flaps attached to the structure that attachto the portion of tissue, the amputation wound having a deep portion anda shallow portion.
 12. The device of claim 10 further comprising a portin the structure that connects to the negative pressure source.
 13. Thedevice of claim 11 wherein negative pressure imparts a compressive forcewith the structure to at least partially collapse the structure therebycausing the deep portion of the amputation wound to close before theshallow portion.
 14. The device of claim 10 wherein the articulatingelements rotate at joints such that the structure collapses along acurved path above the wound opening.
 15. The device of claim 10 furthercomprising a drain element positioned within the wound opening duringwound closure to drain fluid from the wound.
 16. The device of claim 15wherein the drain element comprises drain channels or drain tubes. 17.The device of claim 16 wherein the drain element further comprises alayer of biodegradable material having a plurality of spaced apertures.18. A method for treating an open wound with negative pressure therapycomprising: surgically preparing a wound opening for negative pressuretherapy; applying a flexible structure above the wound, the structurehaving a curved surface overlying the wound; and applying negativepressure to drain fluid from the wound and exert a force on tissue on aside of the wound opening.
 19. The method of claim 18 further comprisingapplying a drain element positioned within the wound opening duringwound closure to drain fluid from the wound.
 20. The method of claim 19wherein the drain element comprises drain channels or drain tubes. 21.The method of claim 20 wherein the drain element further comprises alayer of biodegradable material having a plurality of spaced apertures.22. The method of claim 18 wherein applying the flexible structureincludes attaching a drape that affixes a lateral portion of theflexible structure to tissue surrounding at least a deep portion of thewound, the wound having the deep portion and a shallow portion.
 24. Themethod of claim 22 wherein applying the negative pressure causes theflexible structure to at least partially collapse and causes the lateralportion the apply an inward force to the deep portion of the wound toclose before the shallow portion.
 25. The method of claim 18 wherein aradius of curvature of the flexible structure is different from a radiusof curvature of the tissue surrounding the wound.
 26. The method ofclaim 18, wherein the wound includes an undermined region and a surfaceregion.
 27. The method of claim 26, wherein the flexible structureincludes a bladder.
 28. The method of claim 27, wherein applying thenegative pressure imparts a compressive force on the bladder to impart aforce on a tissue surface surrounding the wound to close wound marginsin the undermined region before closure of wound margins in the surfaceregion.
 29. The method of claim 18, wherein the flexible structurefurther comprises a compression element that contacts the tissue on theside of the wound opening, the compression element configured to apply aforce to the side of the wound opening.